Nearly 20 years after it first stomped onto the screen in 1993, Stephen Spielberg’s special and visual effects masterpiece Jurassic Park is being re-released in 3D this week. However, not unlike earth’s ecosystem itself, the fascinating world of dinosaur paleontology is an ever-changing place. Over the last two decades, some truly astonishing new discoveries have been made, spanning just about every conceivable topic in the biology, behavior, and evolution of these animals. So, to honor this grand cinematic occasion, let’s take a look back at the dinosaurs of Jurassic Park and how recent discoveries have since changed our view of the magnificent creatures in its cast.

1. Triceratops

A series of recent studies has proposed that the distinctive horns above Triceratops’ eyes would grow thicker and curve downward with age. For an account of a 2009 experiment that may help scientists understand how these dreaded weapons were put into practice, go here.

2. Parasaurolophus

We never hear a peep out of them in the movie, but in 1998, Tom Williamson of the New Mexico Museum of Natural History and Science worked with a team of computer scientists to digitally simulate what Parasaurolophus may have actually sounded like some 75 million years ago. Check it out:

3. Dilophosaurus

Though absolutely no evidence exists to suggest that Dilophosaurus was actually venomous as seen in Jurassic Park, one of the animal’s original discoverers, the late Sam Welles of the University of California Museum of Paleontology, quickly became a fan of the film. In the mid-90s, he dedicated a delightfully-informative web page to the biology, unearthing, and cinematic debut of his beloved dinosaur. “I thoroughly enjoyed the movie”, said Welles, “and was very happy to find Dilophosaurus an internationally-known actor.”

4. Brachiosaurus

Could such a massive dinosaur really stand on two limbs without toppling over, as shown in the breathtaking clip above? Given the fact that the beast’s front legs were significantly longer than its back ones (and, hence, the name Brachiosaurus literally means “arm lizard”), paleontologist Heinrich Mallison argued in 2011 that, in Brachiosaurus’ case, rearing would include “a high risk of serious injury should the animal become unbalanced,” though he argued that some other species of sauropods (“long-necked” dinos) would’ve been able to do so.

5. Tyrannosaurus

“I think the hero of this movie is the T. rex,” Spielberg once said. He certainly isn’t the only one to have fallen in love with the “Tyrant Lizard King”: Tyrannosaurus is easily the most exhaustively-studied dinosaur of all time. One of Jurassic Park’s most famous sequences—in which a hungry “rex” hits speeds of 45 miles per hour while charging after a jeep—has come under fire in recent years. A 2002 analysis argued that, for this to occur, 86 percent of its muscle mass would have had to have been concentrated in its legs, a ludicrously implausible notion.

6. Gallimimus

A flock of these ostrich-like dinosaurs are seen stampeding away from a hungry T. rex in the third act of the film. Were the sequence shot today, the creatures’ arms would’ve been positioned differently: notice that the terrified Gallimimus hold their palms downward in this scene.

However, recent findings have confirmed that, in life, the hands of this sinuous dino and its kin would’ve faced each other instead, a position also favored by present-day birds.

7. Velociraptor

Over a decade after its last installment, a fourth film will finally be added to the Jurassic Park franchise next summer. The new movie may still be over a year away, but it’s already managed to stir up some scientific controversy. Director Colin Trevorrow recently tweeted that, in order to preserve series continuity, the “raptors” involved will not be given feathers, despite the overwhelming scientific consensus that these swift predators were at least partially covered with them. A series of bumps known as “quill knobs,” which anchor large feathers in modern birds, were found on the forearms of a Mongolian specimen in 2007. As for the original Jurassic Park, a great deal has been written about the accuracy of its Velociraptors—here's a basic summary.